摘要：为了探究S杂质对CeO₂体系的影响机理,采用基于密度泛函理论的第一性原理,通过S原子代替O原子建立同等条件下不同浓度的CeO_2-xS_x模型,并对CeO₂的晶体结构进行优化,计算并分析体系的几何结构、能带结构、态密度和光学特性。结果表明:S掺杂后CeO₂的晶格常数发生改变;S掺杂使体系的导带和价带均向低能方向移动,随着掺杂浓度的增大,禁带宽度先减小后增大,并在禁带中引入3条杂质能级;CeO₂吸收边红移,并且随着掺杂浓度的增大,对可见光的吸收增强,对紫外光的吸收减弱。

关键词：第一性原理；S 掺杂；杂质能级；光学性质

Abstract：To explore the influence mechanism of CeO₂ system with S impurities, through S atoms replacing O atoms, the first principle based on the density function theory was used to set up the CeO_2-xS_x model with different concentrations under the equal condition. The crystal structure of CeO₂ was optimized. The geometry structure, band structure, density of states and optical properties of the system were calculated and analyzed.The results show that the lattice of CeO₂ distorts after S doping. The doping of S makes the valence band and conduction band move to the direction of low energy. With the increase of the doping concentration, the forbidden band width increases first and then decreases. The doping introduces three levels of impurities in the forbidden band, and results in a different degree of red-shift in the absorption edge of doped CeO₂. With the increase of doping concentration, the absorption of visible light is enhanced, and the absorption of ultraviolet light is weakened.

Keywords: first principle；S doped；impurity level；optical property